1. Field of the Invention
The present invention relates to an electronic control apparatus adapted for a vehicle, not exclusively but preferably a car, and provided with a plurality of control units and a communication circuit providing a connection for communication among the control units.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 2002-314632 discloses a system in which data communication is performed among a plurality of control units. Each of the control units detects whether or not a communication abnormality occurs on the basis of the cycles of received data and, when occurrence of the communication abnormality is detected, each of the control units executes a fail-safe mode.
In the conventional diagnosis of communication abnormality, each of the control units diagnoses an own reception state but cannot diagnose a reception state of the associated control unit or units.
Consequently, the fail-safe mode cannot be properly executed with respect to a reception abnormality of the other associated control unit or units, and there is such a possibility that controllability might largely deteriorate.